Thanks for your input. In the UI it shows:

/mnt
/mnt/Sd
/mnt/Usb (Where here ‘Sd’ & ‘Usb’ represent the labels of both connected drives)

That’s it!
I’ve tried several times all of them with same results, no change. The sizes still reduced to 95 ~ 97.5MB from 128GB each media, that is. Even while going inside the Advanced Settings of root on Luci, taking a closer look, the sda1 path seems not to work and only the sdb1 path “stands” despite after trying to edit the settings. I have done every possible path but to no avail…

Again, I recall back with older software (firmware) when it worked correctly, I did not see the drives inside ‘GL-Samba’ folder as it never showed up to start with, but rather only as with paths: sda1/drive(share) & sdb1/drive(share), and using [only]: “/mnt” in the UI, ignoring everything else.

Something is certainly broken somewhere. These are brand new drives (sd & usb) formatted as NTSF, also despite trying exFAT (just to see), unfortunately with same outcome.